This invention relates generally to improvements in a striking plate, and to an impact means incorporating the striking plate between a pair of spaced rings of a rotor in a disintegrating mill.
One type of disintegrating mill in which the present invention can be utilized is fully disclosed in U.S. Pat. No. 3,047,243 issued July 31, 1962, the disclosure being incorporated and referred to herein.
Disintegrating mills of the type designated as internally-fed impact cage mills are employed to reduce solid granular material, such as stone, ore or other similar material to a finer particle size. The material is forced to travel outwardly by centrifugal force because of rotation of the cages of the mill, and as the particles of material move radially outwardly, they are struck by suitable impact means in the cages which shatter or disintegrate the material to reduce it to smaller size. In the heretofore conventional mills, the striking plate is usually worn severely on the radially inner edge of the leading impact face, resulting in a partially rounded impact face. The rounder this face becomes, the more non-uniform the impact forces become for the different particles. Controlling the direction and hence the relative force of impact of the majority of the particles being processed was the basis for U.S. Pat. No. 3,047,243.
In addition, the leading impact face of the heretofore conventional striking plate has a particular structure and inclination relative to the radius of the rotor so that as a slug of particles strikes the impact face, a certain portion of these particles is retained on the impact face and is impacted by the next slug of particles striking the impact face. There are two negative results from impacting particles to be crushed onto a bed of already crushed particles. First, the impact force and hence the disintegrating effect on the large particles as they hit the residual bed of material is measurably cushioned or reduced, resulting in more oversize particles in the crushed product. Secondly, the residual bed of already crushed or impacted material is subjected to further uncontrolled inter-particle impaction which in turn results in the production of a higher percentage of extreme fines in the finished product.